Computing devices such as network-enabled mobile devices have become ubiquitous and have greatly improved people's ability to access information and communicate with each other, and have become powerful tools for learning and collaboration. However, computing devices can also be used in less productive ways. For instance, some users, in many cases children, spend an inordinate amount of time each day on social media, online games, etc. Such abuses may be detrimental to the users' physical, mental, and social health.